1. Technical Field
The present invention relates to a composition for forming a substrate, and a prepreg and substrate using the same.
2. Description of the Related Art
With the advance of electronic appliances, printed circuit boards are becoming light, thin and miniaturized. In order to meet these requirements, the wiring of printed circuit boards is becoming more complicated and highly-densified. As such, electrical, thermal and mechanical stability are important factors in the manufacture of a substrate. Among these, the coefficient of thermal expansion (CTE) is a particularly important factor influencing reliable manufacture of a substrate.
Further, with the development of advanced technologies, the frequency band used in information and communication equipment is becoming higher. In particular, the frequency band of ultrahigh-speed wireless communication appliances has been broadened to several tens of GHz.
However, the conventional insulating material of printed circuit boards, using an epoxy resin, cannot be used in the high frequency region. Generally, a polymer material, serving as the insulating material of printed circuit boards, must have a low dielectric constant in order to be used in the high-speed high-frequency region. However, since the insulating material using an epoxy resin has a relatively high dielectric constant of 4 or more, it interferes with signal transmission of a circuit in the high frequency region, thus increasing signal loss.
In order to solve the above problem, polytetrafluoroethylene (PTFE) having a low dielectric constant is used as an insulating material of printed circuit boards. However, PTFE is problematic to be used as a raw material of printed circuit board because it has poor mechanical properties and low adhesivity to copper foil although it has excellent electrical properties and corrosion resistance to solvents.
Therefore, it is keenly required to develop substrate materials which can satisfy thermal and mechanical properties required to realize thin and highly-densified integrated circuit patterns and which have excellent electrical properties.